Recently, with westernization of diets, patients of lifestyle-related disease are increasing, resulting in serious medical and social problems. At present, in Japan, the number of diabetic patients is 8,000,000, and the number of diabetic patients plus pre-diabetic patients is 20,000,000. The three main complications of diabetes are retinopathy, nephropathy, and neuropathy. Diabetes is also a cause for arteriosclerosis. Furthermore, diabetes may cause heart diseases and brain diseases.
A person develops diabetes in such a manner that improper diets and life styles, secretion from fat cells due to fatness, or oxidative stress decrease the function of pancreas, causing shortage of insulin that controls blood glucose level or reducing the effect of insulin. Diabetes has symptoms such as frequent urination and increased amount of urination, and increased thirst. However, such symptoms may not enable patients to realize that they develop diabetes, and most patients know their illness when they are subjected to inspection in hospitals etc. This tells why there are so many “silent” diabetic patients. However, at the stage where abnormal symptoms resulting from the complications of diabetes are found in hospitals etc., conditions of the disease have advanced too far, making it difficult to completely cure the disease. In particular, many of the complications of diabetes are difficult to cure, and therefore prevention of diabetes is considered as important like many lifestyle-related diseases. For the prevention, early identification and early determination of therapeutic effect are essential, and there are many inspections for diabetes for this purpose.
When blood contains abnormal amounts of carbohydrates and lipids therein, oxidative stress causes a reaction with protein so that AGEs (Advanced Glycation Endproducts) are produced. AGEs are end products produced via nonenzymatic glycosylation reaction of protein (Maillard reaction). AGEs exhibit yellowish brown color, emit fluorescence, and form crosslink by binding to nearby proteins. AGEs are considered to be deposited on and infuse into blood vessel walls or interact with macrophage which is a part of an immune system to release cytokine which is a protein and to causes inflammation, resulting in arteriosclerosis.
In the case of diabetes, as the blood glucose level increases, the amount of AGEs increases. Accordingly, by monitoring AGEs, it is possible to identify diabetes at an early stage or comprehend progress of diabetes. One example of a method for screening diabetes mellitus by monitoring AGEs is a conventional art in Patent Literature 1. The conventional art of Patent Literature 1 uses a light source, a tissue sampling device, a detector, and a model used to connect detected fluorescence and the condition of the disease. In the conventional art, AGEs are monitored in such a manner that skin of a forearm is irradiated with excitation light and spectrum of fluorescence from AGEs binding to skin collagen is detected. Thus, data is obtained in a non-invasive manner.